Today, over 1,100 functioning satellites orbit our Earth in addition to approximately 2,600 decommissioned satellites. These currently functioning space vehicles provide a wide range of services including Global Positioning System (GPS) navigation aid, telephone communications, television broadcast, weather forecasting, and defense-oriented purposes. Space vehicle technology generally has provided widely used and useful technology, but remains prohibitively expensive to develop, design, and construct a space vehicle for any purpose.
A space vehicle, as used herein, may include various configurations. For instance, a space vehicle may consist of a spacecraft bus alone. In addition, a space vehicle may include the spacecraft bus and a payload, which itself may have different configurations. The payload may be in a non-pressurized, a partially pressurized, or a fully pressurized configuration. In this regard, the payload could include an apparatus chosen based upon the particular mission and electronic components associated with the apparatus. Pressurization of the payload could be applied on the basis of a subset of components of the payload or to the payload as a whole.
Current space vehicle specifications require that space vehicles and components be designed to withstand hostile vibration and shock launch environments, very large operational temperature ranges (e.g., −30 to 150° F./−34 to 66° C.), and vacuum pressure environments. Furthermore, developers typically develop space vehicle technologies optimized specifically for a single mission, requiring significant lead time. An associated challenge, therefore, is that the same design cannot typically be re-used in association with dissimilar mission profiles. Each space vehicle is a custom built unique piece of hardware, with the associated high costs and applicability of use associated with such specialization. Environmental considerations and single-mission profile platforms remain primary drivers for the prohibitive cost of unmanned space vehicles and associated components.
It will be appreciated to those skilled in the art that a vacuum environment, as used herein, refers to the atmospheric environmental conditions as found in the operating envelope of space vehicles as deployed in orbit around the earth or beyond dependent upon mission profile.
A recurring challenge associated with space vehicles relates to thermal management, which plays a major role in the design of space vehicles. This derives from nuances associated with space vehicle component electronic equipment, which has finite environmental limitations particularly associated with temperature range and vacuum environment. This challenge relates to the lack of atmosphere in the operating range of satellites and other space vehicles. Thus, the temperature profile swings drastically based on solar exposure.
A surface of a space vehicle exposed to the sun's radiation receives about 1400 W/m2. As a result, a space vehicle may experience a surface temperature exceeding allowable operational temperatures of component electronic equipment. In operation, the surface temperature of a space vehicle may reach as high as 250° F. or higher.
Furthermore, a surface of a space vehicle not exposed to solar radiation results in a surface temperature well below desirable operational temperatures of components. The surface temperature in this scenario may reach as low as −29° C. (−22° F.) or lower. Both hot and cold temperatures in these scenarios introduce expensive design criteria for the manufacturer.
A problem with some space vehicles is that components are mounted directly to externally facing panels. Thus, such panels experience potentially damaging operational temperature swings based on situational orientation in relation to solar radiation. Many components involve critical electronics that are temperature sensitive electronics, which cannot operate within the broad range of environmentally driven operational temperatures and pressures experienced by a space vehicle, such as those associated with designing for a vacuum, such as outgassing, material tracking contamination migration, corona effects in a low vacuum, etc., without significant design costs associated with mitigation of the operational temperatures and pressures.
It will be appreciated by those skilled in the art that such problems surrounding operational pressures include outgassing of components, material tracking, contamination migration, and corona effects in low vacuum comprise some of the many problems associated with operating in a vacuum environment with electrically powered equipment.
Some space vehicle technologies attempt to solve the problem of operational temperature ranges inherent in space vehicle operating environments through an active thermal radiation system to reject excess heat witnessed by a sun-facing surface of the space vehicle to a shaded surface of the space vehicle. The problems associated with such systems include problems associated with cost, complexity, weight, and reliability. Such systems are expensive to implement. They may occupy critical weight and volume that could otherwise be utilized by additional components and/or payload systems. In order to provide functionality to such systems, dedicated batteries are employed and typically use a significant portion of available space, power, and weight capacities. The failure of such systems results in malfunction or failure of on-board systems, providing an additional point of failure and decreasing overall reliability and life span of the space vehicle.
Other space vehicle technologies employ a thermal working fluid in directed pipes conductively attached to all dissipating components and radiators. An inert gas within a pressurized pipe selectively directs the flow of the working fluid when released from pressurized storage tanks to radiators and dissipating components. Although such a system allows for the removal of batteries from usable payload space, such a system also involves compressors, control valves, and working fluid routing systems. This is problematic, as such systems add weight, numerous failure mechanisms, and cost to the build of the space vehicle. Thus, such systems limit the functional payload capacity that can be integrated within a given space vehicle structure. Furthermore, considerable engineering costs must be expended in order to evaluate and reduce failure modes, not including the need to tailor each platform to the specific mission of each space vehicle build.
With an ever-growing use of communications enabled devices, particularly those reliant on space vehicles and associated platforms, it becomes more critical to enable a cost-efficient and time-expedient solution in the deployment of such platforms. Given the discussion of aforementioned problems associated with space vehicles, the development and deployment of associated space vehicle technology based platforms remains cost prohibitive, heavy in nature, and/or have time intensive lead-time associated with it.